linux-kernel - Re: [PATCH v2 13/20] power: supply: bq25890: Support higher charging voltages through Pump Express+ protocol

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Date:   Tue, 16 Nov 2021 13:14:33 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Hans de Goede <hdegoede@...hat.com>
Cc:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Mark Gross <markgross@...nel.org>,
        Andy Shevchenko <andy@...radead.org>,
        Wolfram Sang <wsa@...-dreams.de>,
        Sebastian Reichel <sre@...nel.org>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Ard Biesheuvel <ardb@...nel.org>, Len Brown <lenb@...nel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Yauhen Kharuzhy <jekhor@...il.com>,
        Tsuchiya Yuto <kitakar@...il.com>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        linux-i2c <linux-i2c@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-efi <linux-efi@...r.kernel.org>
Subject: Re: [PATCH v2 13/20] power: supply: bq25890: Support higher charging
 voltages through Pump Express+ protocol

On Sun, Nov 14, 2021 at 7:04 PM Hans de Goede <hdegoede@...hat.com> wrote:
>
> From: Yauhen Kharuzhy <jekhor@...il.com>
>
> Add a "linux,pump-express-vbus-max" property which indicates if the Pump
> Express+ protocol should be used to increase the charging protocol.
>
> If this new property is set and a DCP charger is detected then request
> a higher charging voltage through the Pump Express+ protocol.
>
> So far this new property is only used on X86/ACPI (non devicetree) devs,
> IOW it is not used in actual devicetree files. The devicetree-bindings
> maintainers have requested properties like these to not be added to the
> devicetree-bindings, so the new property is deliberately not added
> to the existing devicetree-bindings.
>
> Changes by Hans de Goede:
> - Port to my bq25890 patch-series + various cleanups
> - Make behavior configurable through a new "linux,pump-express-vbus-max"
>   device-property
> - Sleep 1 second before re-checking the Vbus voltage after requesting
>   it to be raised, to ensure that the ADC has time to sampled the new Vbus
> - Add VBUSV bq25890_tables[] entry and use it in bq25890_get_vbus_voltage()
> - Tweak commit message

...

> +#define PUMP_EXPRESS_START_DELAY       (5 * HZ)
> +#define PUMP_EXPRESS_MAX_TRIES         6
> +#define PUMP_EXPRESS_VBUS_MARGIN       1000000

Units? Perhaps "_uV"?

...

> +               dev_dbg(bq->dev, "input voltage = %d mV\n", voltage);

Just to be sure, is it indeed "mV" and not "uV"?

...

> +               while (bq25890_field_read(bq, F_PUMPX_UP) == 1)
> +                       msleep(100);

Infinite loop?

Sounds like a good candidate to switch to read_poll_timeout() // note
it accepts any type of (op) with a variadic number of args.

...

> +error:

error_print: ?

> +       dev_err(bq->dev, "Failed to request hi-voltage charging\n");

...

> +       ret = device_property_read_u32(bq->dev, "linux,pump-express-vbus-max",
> +                                      &bq->pump_express_vbus_max);
> +       if (ret < 0)
> +               bq->pump_express_vbus_max = 0;

Isn't it 0 by default?

Anyway, for all optional properties one may use

bq->...property... = $default;
device_property_read_u32(bq->dev, "linux,...property...", &bq->...property...);

I.e. no conditional needed.

-- 
With Best Regards,
Andy Shevchenko